Currently, the tools that are used when operating inside a mill, in order to determine some data about the behavior of certain key parameters are indirect tools, inferences provided by mathematical models and/or external sensors to the mill which provide supposed data about the optimal levels of load, wear of materials, as well as of liners and efficiency in using grinding means.
Such information is not more than just estimates and inferences when considering the lack of concrete tools showing what is really happening inside the mill during operation.
The operational environment of a grinding mill is produced by impact, attrition and abrasion when the mill rotates at a speed between the range of 60 to 85% of its critical speed.
Nowadays it is not possible to know first-hand what is happening inside a mill while this is operating. It can only be inferred the behavior and condition of the load, considering that the great technological barrier is the aggressiveness of the environment inside the mill, such as a SAG mill.
Currently, there have been some attempts to obtain an image from the inside of the mill. The patent application CN101745449A dated 23 Jun. 2010 entitled “Ball mill with capacity to monitor movement in the internal environment” property of YI SUN et al, discloses a camera with a fixed structure in the interior of the ball mill, and is connected to a protective cover. The structure is balanced against clockwise motion so that the structure is isolated from rotation. This makes possible to monitor the behavior of the load in real time. However, this is not positioned in a safe zone, which means that structure must be replaced once it is worn out. This results in the ball mill to be stopped. In addition, the camera does not collect other parameters such as the actual wear, alerts when in presence of detachments of a piece, the absolute position of the load, among other variables.
The Chilean Application 201000402 dated 23 Apr. 2010 entitled “Grinding Ball having the property of transmitting information about its behavior inside the grinding towards an external receiving point”, Property of L. Cerda et al, discloses a grinding body which is incorporated into the load of a SAG mill and which in its interior is provided with a sensor, a microprocessor, a receiver and a transmitter which captures data relative to the behavior of said grinding body being in contact with the grinding and the mill, thereby processing, translating and transmitting said information from and towards an external receiver located on the surrounding space with respect to the grinding body. The grinding body works in the interior of the load and has a sole undefined sensor. However, it does not provide optical information, wear rate, alert in case of a loose piece of the liner, the apparent volumetric filling level and other parameters such as the ones proposed by the present application.